It's very, very easy to forget the immense warts that came along with Drummond after his one year at UConn. He was raw, he was widely seen as lazy, it was evident that he had absolutely zero jump shot (still doesn't), and he didn't have sky-high rebounding numbers. The body was there, and the rest of it was all one big question mark.
Dismissing the collegiate TRob as having "no actual skill" is not a particularly strong argument if comparing to Drummond. While Robinson is not the rim protector Drummond is, he was 4x the passer in college, he grabbed 140% as many rebounds per minute, he scored more than half again as much, he was a much better ball handler, and yes, he had the maturity and motor that Drummond did not.
Drummond would have been a very interesting gamble, and it would have paid off. Robinson was a safe bet that didn't pay off. The outcome did not work, but the decision was quite defensible. Keep in mind that another factor in selecting Robinson was the fact that the Maloofs would not commit to resigning Thompson in the offseason and Petrie had to worry about potentially filling a starting PF slot - where again experience was a pretty important factor. Had Petrie gotten assurances of signing JT in the offseason, we would have taken Lillard, not Drummond, anyway.
The draft is not perfect. There are probably a minimum of five teams (Charlotte, MKG; Cleveland, Waiters; Sacramento, Robinson; Golden State, Barnes; Toronto, Ross) who are kicking themselves for not taking Drummond, and a sixth (Washington, Beal) is at least on the edge. Anthony Davis and perhaps Damian Lillard are the only players that would go ahead of Drummond if the draft were re-run today. There's no point in distorting history to try to make us look bad - this kind of thing happens to dozens of teams in every draft.